ANTI-MAJOR HISTOCOMPATIBILITY COMPLEX ANTIBODY-RESPONSES TO SIMIAN B-CELLS DO NOT PROTECT MACAQUES AGAINST SIVMAC INFECTION

Macaques have been protected against infection with human cell-grown S IVmac by immunization with antigens encoded by the human major histoco mpatibility complex (MHC), Here, we investigated the efficacy of alloi mmunization with simian B cells expressing high levels of MHC class I and class II molecules to confer protection against systemic challenge with simian-grown SIVmac, Eight rhesus macaques were vaccinated with glutaraldehyde-fixed and beta-propiolactone-inactivated herpesvirus pa pio-transformed B cells, Four of the macaques received 5 doses, the ot hers 10, Animals were challenged with rhesus macaque spleen-derived ce ll-free SIVmac. Allogeneic B cells elicited antibody responses to rhes us MHC class I and II but failed to protect animals against infection, Anti-MHC class I antibodies were restricted in specificity and failed to recognize MHC class I from some B lymphoblastoid cell lines (B-LCL s) including a B-LCL from the animal in whose cells the challenge viru s was grown, Vaccinated animals responded to self-MHC class I antigens but not to self-MHC class II antigens from peripheral blood mononucle ar cells (PBMCs), Animals that underwent the shorter immunization regi men had transiently enhanced PBMC-associated virus loads after challen ge, whereas the average virus-infected cell load was reduced in animal s that underwent the more extensive immunization, These results sugges t that antibody responses to allogeneic MHC molecules do not protect a gainst infection with immunodeficiency lentiviruses.